How many moles of helium atoms are there in 2.4x1024 helium atoms?
A)2.4x10^24 mol
B)4.0 mol
C) 6 mol

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.

An object becomes electrically charged when: electrons are created in it electrons from it are destroyed electrons are transferred to it protons from it are destroyed protons are created in it

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?